1 . Field of the Invention
The present invention relates to an expert system which has a knowledge base and an inference unit, executing an inference process with the inference unit by using knowledge stored in the knowledge base to obtain the inference result, and more particularly, effectively building up a knowledge base to automatically verify a knowledge and tune a certainty factor.
2. Description of the Related Art
Recently, thanks to advanced studies in artificial intelligence, a so-called expert system has been developed, which draws a conclusion from experience and provides practical insight of one skilled in the art, by using a computer. The system has been applied to a wide variety of industrial fields.
Synthesis of knowledge base is important in realizing an expert system for achieving specific objects in some industrial field. In particular, to use tools for building up an expert system, such as an expert shell capable of easily realizing the expert system, the main work is to collect knowledge and to prepare knowledge bases. It takes extremely long time to prepare knowledge bases.
To build an expert system for other similar objects in some industrial field knowledge is classified into two categories. One is knowledge common in the industrial fields (i.e., general knowledge on physical laws and principles). The other knowledge is only applicable to specific objects of the fields (i.e., knowledge applied to objects in the fields, or knowledge related to characteristic and rated). These two kinds of knowledge are generated, managed, and executed in one knowledge base paradigm.
To build up an expert system to deal with other similar objects in the same industrial field, referring to former knowledge base, design staff may use those former knowledge bases as fragmental knowledge. However, even though they may extract available knowledge, it is very difficult to apply former knowledge with no change to an expert system which development is required. Therefore, the design staff need to pick up an available knowledge, one by one, from the knowledge base of the former expert system, and to build up new knowledge bases by the selected knowledge again. Enormous time is required to compose knowledge, verify the knowledge, and tune certainty factor.
As described above, in a conventional expert system, not only a knowledge base cannot be built effectively, but also enormous time is needed to perform the verification of knowledge and the tuning of certainty factor.